Decreased neuronal energy production and increased oxidative stress are believed to be major components in the onset of Parkinson's Disease. It is believed that the substantia nigra contains high levels of iron, which helps catalyze oxygen to reactive oxygen species (ROS). The ROS then degrade dopamine-containing neurons. It is further believed that neurotoxins may be the cause of decreased neuronal energy output in the substantia nigra.
The literature describes the general use of anti-oxidants as potent neuroprotective agents for Parkinson's disease. For example, Dugan, Parkin. Relat. Disord., 1002, July. 7, (3) 243–6, describes the use of fullerene-based antioxidants as neuroprotective drugs. In addition, oral administration of ascorbic acid has been tried as a therapy for Parkinson's Disease. To date, however, none of the therapies involving systemic administration of anti-oxidants has been shown to be successful. One possible reason for their failure was their inability to cross the blood brain barrier.